You'd think that going on a strict diet and exercise regimen would help you drop pounds quickly, but most people actually gain weight at first. If this has happened to you, don’t give up on your goals just yet. Not only can certain types of exercise, like strength training, make you gain weight from added muscle, you could also be retaining water.

But what about those cases when the weight gain is actually fat, not muscle or water? There are a couple of scenarios that could explain this. Athletes training for triathlon events and even new runners training for their first 5K may easily make the mistake of abusing the “carb-loading” concept. Eating too much pasta and bread will pack on the pounds, so if you’re carb-loading, make sure you know what you’re doing.

Another common mistake exercisers make is overusing protein bars and drinks. The average protein bar easily packs 300 calories, which isn’t a problem unless you’re eating one right after your workout and then eating a meal on top of it all. Unless you’re burning thousands of calories every day in training, protein bars and calorie-rich protein shakes need to be a meal replacement, not a snack.